package servlets.module.challenge;

import dbProcs.Getter;
import dbProcs.Setter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Locale;
import java.util.Random;
import java.util.ResourceBundle;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import utils.ShepherdLogManager;
import utils.Validate;

/**
 * Cross Site Request Forgery Challenge Target Six <br>
 * <br>
 * Weak Nonce Variety can be broken <br>
 * <br>
 * This file is part of the Security Shepherd Project.
 *
 * <p>The Security Shepherd project is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.<br>
 *
 * <p>The Security Shepherd project is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE. See the GNU General Public License for more details.<br>
 *
 * <p>You should have received a copy of the GNU General Public License along with the Security
 * Shepherd project. If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Mark Denihan
 */
public class CsrfChallengeTargetSix extends HttpServlet {

  private static final long serialVersionUID = 1L;
  private static String moduleHash =
      "2fff41105149e507c75b5a54e558470469d7024929cf78d570cd16c03bee3569";
  private static final String[] csrfArray = {
    "c4ca4238a0b923820dcc509a6f75849b",
    "c81e728d9d4c2f636f067f89cc14862c",
    "eccbc87e4b5ce2fe28308fd9f2a7baf3"
  };
  private static final Logger log = LogManager.getLogger(CsrfChallengeTargetSix.class);
  private static String levelName = "CSRF 6 Target";

  /**
   * CSRF vulnerable function that can be used by users to force other users to mark their CSRF
   * challenge Two as complete.
   *
   * @param userId User identifier to be incremented
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    // Setting IpAddress To Log and taking header for original IP if forwarded from proxy
    ShepherdLogManager.setRequestIp(request.getRemoteAddr(), request.getHeader("X-Forwarded-For"));
    log.debug(levelName + " Servlet");

    // Translation Stuff
    Locale locale = new Locale(Validate.validateLanguage(request.getSession()));
    ResourceBundle errors = ResourceBundle.getBundle("i18n.servlets.errors", locale);
    ResourceBundle csrfGenerics =
        ResourceBundle.getBundle("i18n.servlets.challenges.csrf.csrfGenerics", locale);

    PrintWriter out = response.getWriter();
    out.print(getServletInfo());
    String storedToken = new String();
    try {
      String csrfTokenName = "csrfChallengeSixNonce";
      boolean result = false;
      HttpSession ses = request.getSession(true);
      if (Validate.validateSession(ses)) {
        ShepherdLogManager.setRequestIp(
            request.getRemoteAddr(),
            request.getHeader("X-Forwarded-For"),
            ses.getAttribute("userName").toString());
        log.debug(levelName + " servlet accessed by: " + ses.getAttribute("userName").toString());
        // Get CSRF Token From session
        if (ses.getAttribute(csrfTokenName) == null
            || ses.getAttribute(csrfTokenName).toString().isEmpty()) {
          log.debug("No CSRF Token associated with user");
          Random random = new Random();
          int newToken = random.nextInt(3);
          storedToken = csrfArray[newToken];
          out.write(
              csrfGenerics.getString("target.noTokenNewToken") + " " + storedToken + "<br><br>");
          ses.setAttribute(csrfTokenName, storedToken);
        } else {
          storedToken = "" + ses.getAttribute(csrfTokenName);
        }
        String userId = (String) ses.getAttribute("userStamp");

        String plusId = request.getParameter("userId").trim();
        ;
        log.debug("User Submitted - " + plusId);
        String csrfToken = request.getParameter("csrfToken").trim();
        ;
        log.debug("csrfToken Submitted - " + csrfToken);

        if (!userId.equals(plusId)) {
          if (csrfToken.equalsIgnoreCase(storedToken)) {
            log.debug("Valid Nonce Value Submitted");
            String ApplicationRoot = getServletContext().getRealPath("");
            String userName = (String) ses.getAttribute("userName");
            String attackerName = Getter.getUserName(ApplicationRoot, plusId);
            if (attackerName != null) {
              log.debug(userName + " is been CSRF'd by " + attackerName);

              log.debug("Attempting to Increment ");
              String moduleId = Getter.getModuleIdFromHash(ApplicationRoot, moduleHash);
              result = Setter.updateCsrfCounter(ApplicationRoot, moduleId, plusId);
            } else {
              log.error("UserId '" + plusId + "' could not be found.");
            }
          } else {
            log.debug("User " + plusId + " CSRF attack failed due to invalid nonce");
          }
        } else {
          log.debug("User " + userId + " is attacking themselves");
        }

        if (result) {
          out.write(csrfGenerics.getString("target.incrementSuccess"));
        } else {
          out.write(csrfGenerics.getString("target.incrementFailed"));
        }
      } else {
        out.write(csrfGenerics.getString("target.noSession"));
      }
    } catch (Exception e) {
      out.write(errors.getString("error.funky"));
      log.fatal(levelName + " - " + e.toString());
    }
  }
}
